pefers



1 UNITED M STATES PfgENT OFFICE.

. SAML. CHAMPION AND THOMAS CHAMPIONs OF NVASHINGTON, DISTRICT OFCOLUMBIA.

` BRIDGE;

. Speccation ofLetters Patent No. `11,322, dated July 18, 1854.

Bridges; and we do hereby declare that the' following is a :t'ulll andexact description thereof, reference being had to the accompanyingdrawings, and to the letters of reference marked thereon, in which-Figure l is an elevation of a bridge con-3 structed after our improvedplan; In, thi-si View two sections are shown as component L parts of thebridge, each section being1 mounted upon its own pier. .Figs 3, 4, 5,.i

6, 7, 8, 9 and 10, represent respectively views of the details ofconstruction, which `will presently be more particularly described.

The bridge as represented in the drawings consists of two rigidsections, each of whichv is supported on a` pier beneath its center.Each section consists of two parallel frames (A) united bythe floortimbers and diagonal braces. These frames form the sides of the bridge,and each consists of a central foot or hub (B) and a vertical main post(C) resting upon this hub. Thetop of this` post forms thecenter, whencea series of suspension rods (D) radiate, while the hub or foot uponwhich the post stands, is the center whence a series of'struts or braces(E) radiate. This foot has a concave bottom to fit like a saddle uponthe lower strut,

`which lies horizontally, or extends the entire length of the section ofthe bridge, is on a level with the roadway and carriesthe floor timbers.A suitable number of oblique struts, radiate between the center orvertical A vertical clamppost (F) connects the outer extremif ties ofeach of the oblique struts l (E) with the horizontal strut (Gr).

Suspension rods (D) extending from thehead of the centerl post, areconnected to the top, foot, and in-` termediate points of each clamppost. Eachi clamp post (F) has a socket at its upper ex-4 tremity thattits over the outer extremity ontI a strut. Each suspension rod' whetherit terminates at, or passes beyond a clampl post, is rrnly connectedthereto, so that the whole frame `may be united into one rigid system.As the struts and suspension rods have less weight to sustain, as theyrecede from the centers of tension and compression, theymay therefore beproportionately diminished in size and weight with advantage to thestrength .and durability of the bridge,

the parts ot' which distant from the center,

might be made soheavy that the structure would be crushedand fall by itsown weight.' For the purpose of producing a bridge of the greateststrength with a given weight of material, the struts and suspension rodsare both `made less by gradations, or tapering, as they recede from thecenters of resist-ance to `tension and compression. The suspension rodsare made of bars, and are solid. The struts are tubular, and made of notless than two concentric series or layers of curved plates (fr) anexample of which is seen in Fig. 10, which is a section of a portion ofa tapering tubular strut. The

` plates of each series, or layer, of a tapering tube abut; and theplates of one series break joints with those of the other series. If thestrut diminishes in diameter by gradations, then the plates of eachlayer in each gradation abut; but the plates of` contiguous stepsoverlap. The hub, or foot (B) is of semi-cylindrical form, and may bemost conveniently made of two pieces bolted together. The adjacent sidesof these pieces, have recesses, to form, when the pieces are puttogether, a series of sockets, each of which is for the reception of thefoot, or

inner end of a strut, and confine it firmly in place. The shape of this`foot or hub, is seen more clearly in Fig. 7, which represents itdetached and on an enlarged scale.

The clamp posts are shown in detail in Figs. 5 and 6. Each post consistsof two parts, one to be placed on each side of the struts, and clamped`firmly together by through bolts. The recesses (c), in the adjacentsides of the two parts of the clamp posts, are to embrace the struts,soas to hold them more firmly. Or the posts may be made of at bars, andblocks placed between the struts to fill up the spaces, the bars andblocks being iirmly connected by through bolts. The suspension rods passoutside of the clamp posts, and are held in position by cleats parallelto the posts, but outside of the rods. Bolts are passed through thecleats, rods and posts, to bind the whole lirmly together. In somecases, we prefer to make a single set of through bolts bind together theblocks between the struts, the clamp posts, rods, and cleats.

the sections.

struct-ure, are best seen inv Fig. 2.

When a sectionof bridge, constructed as represented and described, ismounted on a central pivot or carriage on the pier upon which it rests,so as to turn, to open a passage for vessels, or for other purposes, itsconnection' with adjacent sections, must be such that both will be freeto expand and contract, both firmly connected, and at the same timesusceptible of being easily dis-.

connected and again re-conneoted. These objects are accomplished bymeans of the device which we have constructed Jfor uniting the terminalposts of the adjacent ends of This device is best seen in Figs. 3 and 4,the former representing t-he sections connected, and the latterdisconnected. This device consists of two strong latch bars, (J) eachpivoted to the upper end of a. post, so as to be free to swing in aplane parallel to the side of the bridge, but not capable of turninointhe opposite direction. The lower part ot each post, at the adjacentends of contiguous sections, is fitted with a mortise, and key, so thatwhen the bars on t-he two posts are crossed, as shown in Fig. 3, and thekeys `placed between them, the sections will be irmly connected. Thebars are detached to disconnect the two sections, as seen in Fig. t, bythe removal of the keys from the mortises.

If a bridge is only required to extend between two piers, that half ofthe frame which extends beyond the central post on the outer end, may bedispensed with; and the sections should in that case have no break inthe middle of the span, as when the whole frame is balanced on one pier,as

shown and described. A greater or less number of struts and suspensionrods -may be employed, according to the magnitude of the structure andthe judgment of the constructor. If the bridge be built on shore, it maybe transported into place, by a method re- Vcently patented by us.

of the composite rods beingeiiected by making the parts most distantfrom the supports of an equal number of bars or wires with the part atthe support, but of diminished thickness, or making them of fewer barsof the same thickness, as may be preferred.

Having thus described our improved bridge, what we claim therein, anddesire to secure by Letters Patent, is-

l. The combination of tubular braces or struts, made smaller bygradat-ion, or tapering as they extend from the pier or support, withsuspension rods, also made smaller by gradations, or tapering as theyextend from helir pier or support substantially as speci- 2. )Ve alsoclaim the arrangement herein described' of the struts, suspension rods,and clamp posts, vizg-the oblique struts between the center post, andhorizontal strut,

being placed in lines radiating from a common center, and the suspensionrods being also placed in lines, radiating from a common center, abovethat from which the struts radiate, in such manner that each suspensionrod -shall extend from the top of the column'or post (C) over the pieror support, to the foot of one of the clamp posts (F) while each obliquestrut shall extend from t-he footof the post (O) over the pier to thehead of each clamp post, as herein described.

Witnesses:

W. H. CUs'rIs, JAMEs THOMPSON.'

